Interlocking rig mat

ABSTRACT

A pair of disengageably interlocking rig mats are provided. The rig mats are engaged to prevent longitudinal separation. An interlocking mechanism of key and receiver is provided. The key is lockably, slidably engaged with the receiver by lateral movement of one mat relative to the other. The mats are configured such that the interlocking mechanism is protected from dirt and debris.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patent application Ser. No. 12/609,859 filed Oct. 30, 2009, which claims priority from Canadian Patent Application No. 2,642,380 filed Oct. 30, 2008. Each of these applications is hereby incorporated by reference in its entirety as if set forth herein in full.

FIELD OF THE INVENTION

The present invention relates to a rig mat having disengagable means for locking to another rig mat.

BACKGROUND OF THE INVENTION

“Rig mats” are very rugged, load-bearing mats used, for example, to support the base of a drilling rig in the oil and gas industry or to form a roadway over which heavy, loaded trucks may pass, where the terrain is unstable or environmentally sensitive.

A typical conventional rig mat may comprise:

-   -   a rectangular peripheral frame formed by wide flanged, steel         I-beams that are welded together at each end to form the four         corners of the rectangular frame;     -   one or more longitudinal and/or transversely extending I-beams         inserted to reinforce the rectangular frame; and     -   a plurality of removable thick wooden logs of square         cross-section that fill the openings defined by the I-beams,         whereby the logs are bracketed at their ends by the I-beam         flanges, and whereby the logs and I-beams combine to form a         horizontal load-bearing wall.

Often, these individual mats must be aligned longitudinally and/or adjacent to one another to form a larger assembly. Accordingly, it is important to ensure that the mats do not shift, or move away from each other, after installation. In order to reduce movement, individual mats are commonly manufactured with interlocking elements along each end or along the sides of the mats. These elements can be disengagably interlocked to fasten mats together, thereby forming a cohesive assembly. Typically, the interlocking elements are engaged or disengaged by manipulating one of the mats, such as by raising, dropping or tilting the mat relative to another mat that remains flat on the ground.

Canadian Patents Nos. 2,348,328 and 2,364,968, issued to David and James Stasiewich, on Oct. 22, 2002 and Jun. 22, 2004, respectively, each disclose a mat-type apparatus, which are examples of the foregoing. FIGS. 1 and 2 herein also depict side sectional views of two prior art locking element assemblies that are presently in commercial use.

One problem, however, that characterizes prior art rig mats having disengagable interlocking element assemblies is that mud, dirt and/or ice can accumulate and block in between the locking elements, thereby making the engagement and disengagement of two adjoining mats difficult. There is a need, therefore, for a rig mat having interlocking elements that better resist blockage with mud, ice and the like and which can be engaged or disengaged in a simple fashion.

SUMMARY OF THE INVENTION

In accordance with the invention, rig mats are provided having end locking elements that may be slidably engaged or disengaged by lateral or sideways movement of one mat relative to the other.

In one embodiment a pair of rig mats, capable of being disengagably interlocked in longitudinal alignment are provided, each rig mat comprising: a rectangular frame having first and second ends, at least one key element mounted to the first end and at least one receiver element mounted to the second end; the key element(s) of one frame being formed so as to disengagably interlock with the receiver element(s) of the other frame when they are laterally and slidably engaged; the key element(s) of said one frame and the receiver element(s) of said other frame being positioned so that they can laterally and slidably engage, when the first end of the one frame abuts and is offset relative to the second end of the other frame and the key element(s) are adjacent to and aligned with the receiver elements, in response to lateral displacement of the one frame, to bring the two frames into longitudinal alignment.

According to an optional feature, each frame is further equipped along one side with at least one downwardly opening bracket and along its other side with at least one upwardly opening bracket so that the frames may be interlocked to prevent lateral separation by lowering one frame relative to the other so that the downwardly opening bracket(s) engage the upwardly opening bracket(s).

In the case where the frames are equipped with both end and side brackets and the frames are aligned longitudinally so that the key elements of one mat are in position to slide laterally into the receiving elements of the other mat, the locking brackets may be engaged by:

-   -   tilting said one mat by raising its rear end;     -   sliding said one mat laterally to fully engage the key and         receiving elements; and     -   then lowering the rear end of the tilted mat to engage its         downwardly opening side locking brackets with the upwardly         opening side locking brackets of an adjacent mat.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view showing one commercially available end locking element assembly in accordance with the prior art.

FIG. 2 is a side sectional view of another commercially available and locking element assembly in accordance with the prior art;

FIG. 3 is a perspective view of a rig mat showing two opposing ends of the rig mat, one end being equipped with a pair of receiver elements and the other with a pair of key elements (hereinafter referred to as ‘receivers’ and ‘keys’);

FIG. 3A is a perspective side view of part of the rig mat shown in FIG. 3;

FIG. 4 is a perspective view showing a plurality of rig mats in the course of being assembled to form a wider mat;

FIG. 5 is a perspective view showing the front end of one mat equipped with keys, adjacent the rear end of another mat equipped with receivers; and

FIG. 6 is a side view, taken along the line VI-VI in FIG. 3, showing logs as they would be inserted between the central and side I-beams of a mat;

FIG. 7 is a perspective view showing a receiver and a key engaged.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is made to FIGS. 1-7.

In use a plurality of rig mats 1 will be interlocked end to end to form a longitudinally aligned arrangement or, alternatively, they will also be interlocked laterally to form a wider arrangement (as shown in FIG. 4).

One such rig mat 1 will now be described.

The rig mat 1 comprises a rectangular frame 2 formed of steel wide-flanged I-beams (hereinafter referred to as ‘beams’). The frame has first and second ends 2 a, 2 b. The frame 2 is formed by a pair of side beams 3 a, 3 b, a first end beam 4 a and a second end beam 4 b. In the drawings the end beam 4 a is shown as the front beam and the end beam 4 b as the rear beam. Each of the side beams 3 a, 3 b have top and bottom flanges 5, 6. The front end beam 4 a has only a top flange 5 while the rear end beam 4 b has top and bottom flanges 5, 6. The side and end beams 3 a, 3 b/4 a, 4 b are welded together at their ends. As shown, the frame 2 may be reinforced with an additional longitudinally extending, central beam 7 and a plurality of laterally extending cross beams, welded in place. Wooden logs 9 of square cross-section are inserted to fill the openings 10 between the I-beams. The ends of the logs 9 are bracketed between and secured by the flanges 5, 6.

Web 14 of the laterally extending, front end beam 4 a has a pair of laterally spaced apart keys 15 welded thereto. Each key 15 comprises a web 16 welded to and projecting forwardly and horizontally from the front beam web 14. An elongated head 17 is connected to the forward end of the key web 16 to complete a generally T-shaped structure.

A pair of laterally spaced apart, tubular receivers 20 are positioned between the top and bottom flanges 5, 6 of the rear end beam 4 b. The receivers 20 are welded in place to the flanges between which they are bracketed. They protrude beyond the longitudinal edges of the flanges.

Each receiver 20 is shown as a length of steel pipe having a bore 21. The protruding portion 22 of the receiver side wall 23 forms a slot 24 extending from one end of the pipe, part way along its length. The non-slotted portion of the pipe wall forms a stop 25.

The slot 24 is dimensioned so as to slidably receive the web 16 of a key 15. The enlarged head 17 of the key 15 is dimensioned so as to be receivable in the pipe bore 21 but is too large to pass through the slot 24.

Broadly stated, the keys 15 of one frame and the receivers 20 of the other frame are formed so as to interlock when they are laterally and slidably engaged, to prevent longitudinal separation of the frames 2.

The stops 25 function to terminate the lateral advance of the key heads 17 when the frames 2 have been longitudinally aligned.

As shown in FIGS. 3, 3A and 4, one side beam 3 a has a downwardly opening bracket 26 welded to it while the other side beam 3 b has an upwardly opening slot 29 formed by plate 28 and top flange 5. If two frames are to be locked together in side by side relationship, one frame can be lowered to the other so that the bracket 26 drops into the slot 29 when the front end and rear ends of the frames are aligned.

The described assembly has been shown to have the following advantages:

-   -   the overhead shielding by the flanges and the tubular nature of         the receiver serve to minimize the entry of dirt from above,         which would impede movement of the keys; and     -   the sideways withdrawal of the key from the receiver is         relatively easy to carry out. 

1. A pair of rig mats capable of being disengagably interlocked in longitudinal alignment, each rig mat comprising: a rectangular frame having first and second ends, at least one key element mounted to the first end and at least one receiver element mounted to the second end; the key element(s) of one frame being formed so as to interlock with the receiver element(s) of the other frame when they are laterally and slidably engaged; the key element(s) of said one frame and the receiver element(s) of said other frame being positioned so that they can laterally and slidably engage, when the first end of the one frame abuts the second end of the other frame and the key element(s) are adjacent to and aligned with the receiver elements, in response to lateral displacement of the one frame to bring the two frames into longitudinal alignment.
 2. The rig mats as set forth in claim 1 wherein: each frame is formed by longitudinally and laterally extending steel I-beams; each receiver element is tubular, has a bore and is welded in position between the flanges of a laterally extending I-beam, said receiver element having a side wall portion forming a slot extending part way along the length of the receiver element from one end thereof, whereby a stop is provided at the other end of the slot; and each key element comprises a key web welded in position to a laterally extending I-beam web so as to project horizontally therefrom, said key web being dimensioned so as to be received by the slot, said head being dimensioned so as to be received in the bore of the receiver element but being too large to pass through the slot; the stop being located so as to engage the key web of a key element when the one frame has been laterally displaced to bring the two frames into longitudinal alignment. 